Chronic stress has been implicated as a contributing factor underlying a range of chronic and infectious disease processes, as well as more immediate aspects of daily function and quality of life in the aging adult. Given this, the development of nonpharmacologic approaches that may improve psychological health as well as mitigate stress-induced aberrations in cardiovascular, neuroendocrine, and immune responses related to disease remains a critical area for systematic study. Regular physical activity has been identified as a promising, though little studied, method for positively influencing both physiological and psychological responses to stress in older adults. While the relatively few controlled studies of the effects of aerobic activity on stress-related response are encouraging, a number of dimensions remain virtually unexplored, including the effects of exercise on immune response and other physiological parameters in older adults; and the use of promising home-based activity interventions in chronically stressed older populations, such as family caregivers, who could particularly benefit from physical activity interventions but whose circumstances typically prohibit attendance at traditional class-based programs. To undertake a comprehensive, state-of-the-art inquiry of the effects of physical activity on stress-related response in family caregivers, an understanding of the array of biomedical as well as behavioral and psychological processes associated with each is needed. The current proposal represents a 2-year extension of a 3-year Special Emphasis Research Career Award in Behavioral Geriatrics focused on the study of physical activity and stress in older adults. The first three years of this award were dedicated to obtaining systematic training in methods of measuring cardiovascular, neuroendocrine, and endocrine responses to stress in both the laboratory and the field. The purpose of the current proposal is to: (1) extend these systematic training experiences to the area of immune function, which represents a critical dimension of the body's physiological response to stress, and (2) conduct a controlled feasibility study investigating the role of regular physical activity in influencing stress-related response in a sample of older women caregivers. The proposed course of interdisciplinary educational experiences takes advantage of the unique resources at Stanford University, as well as the expertise of three of the top research teams in psychoneuroimmunology in the U.S. The proposed training and research goals are designed to extend current knowledge related to the objective assessment of levels of physical demand and functioning in caregivers, and the development of optimal physical activity training regimens for enhancing physical and psychological function and quality of life in this important population segment. The procedures and results from this proposal will subsequently be applied in a larger-scale investigation of the effects of physical activity on stress-related response in this population.